When working with multi-module projects, it is helpful to centralize dependencies in a single location rather than having them spread across many build files, especially for common libraries such as the Android support libraries and the Firebase libraries.
One recommended way is to separate the Gradle build files, with one build.gradle
per module, as well as one in the project root and another one for the dependencies, for example:
root
+- gradleScript/
| dependencies.gradle
+- module1/
| build.gradle
+- module2/
| build.gradle
+- build.gradle
Then, all of your dependencies can be located in gradleScript/dependencies.gradle
:
ext {
// Version
supportVersion = '24.1.0'
// Support Libraries dependencies
supportDependencies = [
design: "com.android.support:design:${supportVersion}",
recyclerView: "com.android.support:recyclerview-v7:${supportVersion}",
cardView: "com.android.support:cardview-v7:${supportVersion}",
appCompat: "com.android.support:appcompat-v7:${supportVersion}",
supportAnnotation: "com.android.support:support-annotations:${supportVersion}",
]
firebaseVersion = '9.2.0';
firebaseDependencies = [
core: "com.google.firebase:firebase-core:${firebaseVersion}",
database: "com.google.firebase:firebase-database:${firebaseVersion}",
storage: "com.google.firebase:firebase-storage:${firebaseVersion}",
crash: "com.google.firebase:firebase-crash:${firebaseVersion}",
auth: "com.google.firebase:firebase-auth:${firebaseVersion}",
messaging: "com.google.firebase:firebase-messaging:${firebaseVersion}",
remoteConfig: "com.google.firebase:firebase-config:${firebaseVersion}",
invites: "com.google.firebase:firebase-invites:${firebaseVersion}",
adMod: "com.google.firebase:firebase-ads:${firebaseVersion}",
appIndexing: "com.google.android.gms:play-services-appindexing:${firebaseVersion}",
];
}
Which can then be applied from that file in the top level file build.gradle
like so:
// Load dependencies
apply from: 'gradleScript/dependencies.gradle'
and in the module1/build.gradle
like so:
// Module build file
dependencies {
// ...
compile supportDependencies.appCompat
compile supportDependencies.design
compile firebaseDependencies.crash
}
A less verbose approach for centralizing library dependencies versions can be achieved by declaring the version number as a variable once, and using it everywhere.
In the workspace root build.gradle
add this:
ext.v = [
supportVersion:'24.1.1',
]
And in every module that uses the same library add the needed libraries
compile "com.android.support:support-v4:${v.supportVersion}"
compile "com.android.support:recyclerview-v7:${v.supportVersion}"
compile "com.android.support:design:${v.supportVersion}"
compile "com.android.support:support-annotations:${v.supportVersion}"